With an increasing number of external contacts, it becomes more and more difficult to reserve a sufficiently large and stable area on which the external contacts of a semiconductor chip can be arranged. In this case, the external contacts differ from the flip-chip contacts in terms of their order of magnitude. Flip-chip contacts, which are arranged immediately on contact areas of a semiconductor chip, have microscopically small dimensions, i.e., the flip-chip contacts can be measured only under an optical microscope. In this connection, flip-chip contacts are understood to mean both microscopically small solder balls or contact bumps of about 150 to 250 μm in external diameter, and also microscopically small surface contacts, i.e., “solid” contacts, which, with external dimensions of about 15 to 25 μm, are an order of magnitude smaller than solder balls or contact bumps using flip-chip technology. On the other hand, external contacts have macroscopically large dimensions, which are visible and measurable with the naked eye and have dimensions in the range from 0.5 to 2 mm.
Consequently, if the number of external contacts increases, then the external dimensions of the electronic components become larger and can far exceed the size of the semiconductor chip, which bears the flip-chip contacts. At the same time, as the chip becomes larger, so do the problems of thermal equalization between the microscopically small contacts of the semiconductor chip and a rewiring plate made of circuit board material, such as glass fiber-reinforced plastic, which can accommodate the large number of external contacts and is permanently connected to the semiconductor chip via the flip-chip contacts.
Since the thermal expansion coefficient of the semiconductor chip, in particular, of silicon, is about 4 ppm/° K and a circuit board material with glass fiber reinforcement, which bears the macroscopically large external contacts, has an expansion coefficient between 13 and 16 ppm/° K, in particular, the microscopically small flip-chip contacts of a silicon semiconductor chip, which are arranged at the outer edges of the semiconductor chip, are stressed. This stress leads to breaks. As a result, the entire component becomes unserviceable.
A further problem results from the fact that the macroscopically large external contacts of the component, which can consist of solder balls or solder bumps and are to be soldered to a circuit board of a primary circuit arrangement, represent a relatively rigid connection to the primary circuit arrangement. The external contacts can also break with respect to the primary circuit under thermal stress.
In large-area semiconductor chips with a high flip-chip contact density and large-area rewiring plates for electronic components having a high external contact density, an electronic component which can be connected with higher reliability to a primary circuit arrangement with a reduction in the shear stress of the external contact areas and external contacts, and the shear stress of the microscopically small flip-chip contacts is desirable.